The human skeleton is composed of 206 individual bones that perform a variety of important functions, including support, movement, protection, storage of minerals, and formation of blood cells. To ensure that the skeleton retains its ability to perform these functions, and to reduce pain and disfigurement, bones that become damaged should be repaired promptly and properly. Typically, a cut or fractured bone is treated using a fixation device, which reinforces the bone and keeps it aligned during healing. Fixation devices may include external fixation devices (such as casts or fixators) and/or internal fixation devices (such as bone plates, nails (rods), and/or bone screws, among others).
Despite the use of fixation devices, bones may heal with a reduced length. For example, fractures of the radius bone in the forearm often result in radial shortening due to axial tension exerted by soft tissue as the fractures heal. Accordingly, the other forearm bone, the ulna, becomes longer relative to the radius. As a result, the distal ulna may impinge on the carpal bones of the wrist, causing inflammation and pain. A common treatment for this condition involves shortening the ulna through osteotomy to restore proper relative lengths of the ulna and radius.
In other cases, a bone may grow to an abnormal relative length that affects proper skeletal function. For example, due to a developmental defect, the ulna may be longer than normal such that the ulna impinges on the carpal bones.
Osteotomy systems for shortening bones have been disclosed by others. Generally, these systems involve a guide that physically directs a saw through a bone according to the position of the guide. However, these systems may suffer from various inadequacies, such as lack of flexibility and/or speed in guide positioning.